Aristotle
Aristotle (Greek:384 BC – 322 BC) was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology. Together with Plato and Socrates (Plato's teacher), Aristotle is one of the most important founding figures in Western philosophy. Aristotle's writings were the first to create a comprehensive system of Western philosophy, encompassing morality and aesthetics, logic and science, politics and metaphysics.
Aristotle's views on the physical sciences profoundly shaped medieval scholarship, and their influence extended well into the Renaissance, although they were ultimately replaced by Newtonian physics. In the zoological sciences, some of his observations were confirmed to be accurate only in the 19th century. His works contain the earliest known formal study of logic, which was incorporated in the late 19th century into modern formal logic. In metaphysics, Aristotelianism had a profound influence on philosophical and theological thinking in the Islamic and Jewish traditions in the Middle Ages, and it continues to influence Christian theology, especially the scholastic tradition of the Catholic Church. His ethics, though always influential, gained renewed interest with the modern advent of virtue ethics. All aspects of Aristotle's philosophy continue to be the object of active academic study today. Though Aristotle wrote many elegant treatises and dialogues (Cicero described his literary style as "a river of gold"), it is thought that the majority of his writings are now lost and only about one-third of the original works have survived.
Physics
The five elements
Aristotle proposed a fifth element, aether, in addition to the four proposed earlier by Empedocles.
1: Earth, which is cold and dry; this corresponds to the modern idea of a solid.
2: Water, which is cold and wet; this corresponds to the modern idea of a liquid.
3: Air, which is hot and wet; this corresponds to the modern idea of a gas.
4: Fire, which is hot and dry; this corresponds to the modern idea of heat.
5: Aether, which is the divine substance that makes up the heavenly spheres and heavenly bodies (stars and planets).
Each of the four earthly elements has its natural place. All that is earthly tends toward the center of the universe, i.e. the center of the Earth. Water tends toward a sphere surrounding the center. Air tends toward a sphere surrounding the water sphere. Fire tends toward the lunar sphere (in which the Moon orbits). When elements are moved out of their natural place, they naturally move back towards it. This is "natural motion"—motion requiring no extrinsic cause. So, for example, in water, earthy bodies sink while air bubbles rise up; in air, rain falls and flame rises. Outside all the other spheres, the heavenly, fifth element, manifested in the stars and planets, moves in the perfection of circles.
Optics
Aristotle held more accurate theories on some optical concepts than other philosophers of his day. The earliest known written evidence of acamera obscura can be found in Aristotle's documentation of such a device in 350 BC in Problemata. Aristotle's apparatus contained a dark chamber that had a single small hole, or aperture, to allow for sunlight to enter. Aristotle used the device to make observations of the sun and noted that no matter what shape the hole was, the sun would still be correctly displayed as a round object. In modern cameras, this is analogous to the diaphragm. Aristotle also made the observation that when the distance between the aperture and the surface with the image increased, the image was magnified.
Chance and spontaneity
According to Aristotle, spontaneity and chance are causes of some things, distinguishable from other types of cause. Chance as an incidental cause lies in the realm of accidental things. It is "from what is spontaneous" (but note that what is spontaneous does not come from chance). For a better understanding of Aristotle's conception of "chance" it might be better to think of "coincidence": Something takes place by chance if a person sets out with the intent of having one thing take place, but with the result of another thing (not intended) taking place. For example: A person seeks donations. That person may find another person willing to donate a substantial sum. However, if the person seeking the donations met the person donating, not for the purpose of collecting donations, but for some other purpose, Aristotle would call the collecting of the donation by that particular donator a result of chance. It must be unusual that something happens by chance. In other words, if something happens all or most of the time, we cannot say that it is by chance.
There is also more specific kind of chance, which Aristotle names "luck", that can only apply to human beings, since it is in the sphere of moral actions. According to Aristotle, luck must involve choice (and thus deliberation), and only humans are capable of deliberation and choice. "What is not capable of action cannot do anything by chance
Motion
Aristotle defined motion as the actuality of a potentiality as such.[Aquinas suggested that the passage be understood literally; that motion can indeed be understood as the active fulfillment of a potential, as a transition toward a potentially possible state. Because actuality and potentiality are normally opposites in Aristotle, other commentators either suggest that the wording which has come down to us is erroneous, or that the addition of the "as such" to the definition is critical to understanding it.
Causality, The Four Causes
Aristotle suggested that the reason for anything coming about can be attributed to four different types of simultaneously active causal factors:
Material cause describes the material out of which something is composed. Thus the material cause of a table is wood, and the material cause of a car is rubber and steel. It is not about action. It does not mean one domino knocks over another domino.
The formal cause is its form, i.e. the arrangement of that matter. It tells us what a thing is, that any thing is determined by the definition, form, pattern, essence, whole, synthesis or archetype. It embraces the account of causes in terms of fundamental principles or general laws, as the whole (i.e., macrostructure) is the cause of its parts, a relationship known as the whole-part causation. Plainly put the formal cause is the idea existing in the first place as exemplar in the mind of the sculptor, and in the second place as intrinsic, determining cause, embodied in the matter. Formal cause could only refer to the essential quality of causation. A more simple example of the formal cause is the blueprint or plan that one has before making or causing a human made object to exist.
The efficient cause is "the primary source", or that from which the change or the ending of the change first starts. It identifies 'what makes of what is made and what causes change of what is changed' and so suggests all sorts of agents, nonliving or living, acting as the sources of change or movement or rest. Representing the current understanding of causality as the relation of cause and effect, this covers the modern definitions of "cause" as either the agent or agency or particular events or states of affairs. More simply again that which immediately sets the thing in motion. So take the two dominos this time of equal weighting, the first is knocked over causing the second also to fall over. This is effectively efficient cause.
The final cause is its purpose, or that for the sake of which a thing exists or is done, including both purposeful and instrumental actions and activities. The final cause or telos is the purpose or end that something is supposed to serve, or it is that from which and that to which the change is. This also covers modern ideas of mental causation involving such psychological causes as volition, need, motivation or motives, rational, irrational, ethical, and all that gives purpose to behavior.
Aristotle marked two modes of causation: proper (prior) causation and accidental (chance) causation. All causes, proper and incidental, can be spoken as potential or as actual, particular or generic. The same language refers to the effects of causes, so that generic effects assigned to generic causes, particular effects to particular causes, operating causes to actual effects. Essentially, causality does not suggest a temporal relation between the cause and the effect.